The present invention relates to a method of polishing a film to be polished, in which a plurality of films or a plurality of portions of a patterned film to be polished is polished by a CMP method, so that the thickness of these films or portions to be polished is adjusted to a predetermined value.
In view of demands for smaller sizes, higher-density recording capabilities, etc., the accuracy in thickness of magnetic poles in thin-film magnetic heads, magnetic poles of perpendicular magnetic recording heads in particular, has recently been required to become higher. For example, a normal magnetic pole has a thin rod shape. For instance, the thickness of a main magnetic pole of a perpendicular magnetic recording head is set to several hundred nanometers, whereas its tolerance is about 10%.
Known as a method of precisely adjusting the thickness of a film in a magnetic pole or the like is a CMP method using a stopper film (see, for example, Japanese Patent Application Laid-Open Nos. HEI 8-102014 and HEI 9-246219).